package com.TT.ticket.threadPool;

import sun.rmi.runtime.Log;

import java.util.concurrent.RecursiveTask;

/**
 * 如何使用ForkJoin
 * 1.ForkJoinPool 通过它来执行
 * 2.计算任务 ForkJoinPool.execute(ForkJoinTask task)
 * 3.计算类要继承 ForkJoinTask
 */
public class ForkJoinDemo extends RecursiveTask<Long> {

    private Long start;
    private Long end;

    //临界值
    private Long temp = 10000L;

    public ForkJoinDemo(Long start, Long end) {
        this.start = start;
        this.end = end;
    }

    //计算方法
    @Override
    protected Long compute() {
        if ((end - start) < temp) {
            Long sum = 0L;
            for (Long i = start; i <= end; i++) {
                sum += i;
            }
            return sum;
        } else {  //ForkJoin 递归
            long middle = (start + end) / 2;
            ForkJoinDemo task1 = new ForkJoinDemo(start, middle);
            task1.fork();
            ForkJoinDemo task2 = new ForkJoinDemo(middle + 1, end);
            task2.fork();

            return task1.join() + task2.join();
        }
    }
}
